Leo,
The function that you are seeking is called "Nesting" and it is part of EFI Fiery XF 3.0 and 4.1.
If you have Colorproof XF, you would need to add the "Production Option" for (around) $500.00.
This is right from the brochure (and our web site):
Nesting: This function saves on material and reduces costs by enabling you to output any number of files together in one single job – even different file formats and files with different color spaces. The preview window also makes daily work easier, allowing you to view and edit the nesting layout using a wide range of functions such as moving, scaling, rotating, flipping and cropping. In addition, you can order, align and distribute multiple pages simultaneously.
FineEye | EFI Fiery® XF